This invention relates generally to container systems for the storing and delivering of liquids. More particularly, this invention relates to integral container systems such as flexible I.V. bags which have the capacity to separately store and subsequently dispense a second substance such as a medicament into a liquid diluent before delivery of the solution to its end use. As will be seen, the present invention exhibits particular utility in the pharmaceutical field. Accordingly much of the discussion herein relates to the pharmaceutical applications, particularly flexible I.V. bags. However, it should be noted that the present invention is not limited to these as other applications in which it provides advantages will become apparent to those skilled in the art. For example, the present invention may prove useful in the handling of photographic chemicals or analytical laboratory solutions, etc.
Container systems which can hold separately two components and subsequently mix those components are especially beneficial in the pharmaceutical field when working with a medicament which is reactive or relatively unstable when mixed with its intended diluent. For example, certain antibiotics have a useful life of only 6 to 12 hours after being mixed with their diluent for intravenous administration. In light of this, a hospital pharmacy is often required to keep a medicament and its diluent in completely separate containers and then to use some independent means for transferring one into the other just prior to delivery. A common practice is to keep the medicament in a glass vial with a pierceable stopper, to draw the medicament out with a cannula and syringe, and to use the cannula and syringe to inject the medicament into the container of the diluent just prior to delivery to the patient. Naturally, this method is tedious and introduces opportunities for error, contamination, and undue delay. Also, transferring by cannula and syringe is not feasible unless the medicament is in liquid form. As a result, when transferring a powdered medicament in this way, it is first necessary to inject a quantity of diluent into the vial to dissolve the powder thereby adding one more step to the process and adding one more possible source of contamination and error.
Another factor present in the pharmaceutical field is that one is required by chemical considerations and by law to store medicaments for long periods of time only in containers made by specified materials. Although glass and rubber are approved for a wide variety of medicaments, particular plastics have received government approval to be used in containers for only a limited number of medicaments. This is unfortunate because these plastics have proven superior to glass in storing and delivering intravenous liquids. In particular, the plastic flexible I.V. bag is often easier to fabricate, fill, and use--all the while maintaining sterility--than the glass I.V. bottle.
Some containers have previously been developed for storing different components separately so they can be intermixed later. However, an effective seal is often not maintained in such containers between the two components to be intermixed particularly in the face of the rigors of handling and shipping. Additionally, containers used in pharmaceutical applications must be completely sterile. Although relatively simple in configuration, the arrangement of parts in some containers makes them difficult to sterilize unless the entire device is assembled in a totally sterile environment. Such manufacture is tremendously expensive. Furthermore, none of these devices use different materials for contacting each of the components.